Saturday, March 10, 2018

Technology lock-in accidents

image: diagram of molten salt reactor

Organizational and regulatory features are sometimes part of the causal background of important technology failures. This is particularly true in the history of nuclear power generation. The promise of peaceful uses of atomic energy was enormously attractive at the end of World War II. In abstract terms the possibility of generating useable power from atomic reactions was quite simple. What was needed was a controllable fission reaction in which the heat produced by fission could be captured to run a steam-powered electrical generator.

The technical challenges presented by harnessing nuclear fission in a power plant were large. Fissionable material needed to be produced as useable fuel sources. A control system needed to be designed to maintain the level of fission at a desired level. And, most critically, a system for removing heat from the fissioning fuel needed to be designed so that the reactor core would not overheat and melt down, releasing energy and radioactive materials into the environment.

Early reactor designs took different approaches to the heat-removal problem. Liquid metal reactors used a metal like sodium as the fluid that would run through the core removing heat to a heat sink for dispersal; and water reactors used pressurized water to serve that function. The sodium breeder reactor design appeared to be a viable approach, but incidents like the Fermi 1 disaster near Detroit cast doubt on the wisdom of using this approach. The reactor design that emerged as the dominant choice in civilian power production was the light water reactor. But light water reactors presented their own technological challenges, including most especially the risk of a massive steam explosion in the event of a power interruption to the cooling plant. In order to obviate this risk reactor designs involved multiple levels of redundancy to ensure that no such power interruption would occur. And much of the cost of construction of a modern light water power plant is dedicated to these systems -- containment vessels, redundant power supplies, etc. In spite of these design efforts, however, light water reactors at Three Mile Island and Fukushima did in fact melt down under unusual circumstances -- with particularly devastating results in Fukushima. The nuclear power industry in the United States essentially died as a result of public fears of the possibility of meltdown of nuclear reactors near populated areas -- fears that were validated by several large nuclear disasters.

What is interesting about this story is that there was an alternative reactor design that was developed by US nuclear scientists and engineers in the 1950s that involved a significantly different solution to the problem of harnessing the heat of a nuclear reaction and that posed a dramatically lower level of risk of meltdown and radioactive release. This is the molten salt reactor, first developed at the Oak Ridge National Laboratory facility in the 1950s. This was developed as part of the loopy idea of creating an atomic-powered aircraft that could remain aloft for months. This reactor design operates at atmospheric pressure, and the technological challenges of maintaining a molten salt cooling system are readily solved. The fact that there is no water involved in the cooling system means that the greatest danger in a nuclear power plant, a violent steam explosion, is eliminated entirely. Molten salt will not turn to steam, and the risk of a steam-based explosion is removed completely. Chinese nuclear energy researchers are currently developing a next generation of molten salt reactors, and there is a likelihood that they will be successful in designing a reactor system that is both more efficient in terms of cost and dramatically safer in terms of low-probability, high-cost accidents (link). This technology also has the advantage of making much more efficient use of the nuclear fuel, leaving a dramatically smaller amount of radioactive waste to dispose of.

So why did the US nuclear industry abandon the molten-salt reactor design? This seems to be a situation of lock-in by an industry and a regulatory system. Once the industry settled on the light water reactor design, it was implemented by the Nuclear Regulatory Commission in terms of the regulations and licensing requirements for new nuclear reactors. It was subsequently extremely difficult for a utility company or a private energy corporation to invest in the research and development and construction costs that would be associated with a radical change of design. There is currently an effort by an American company to develop a new-generation molten salt reactor, and the process is inhibited by the knowledge that it will take a minimum of ten years to gain certification and licensing for a possible commercial plant to be based on the new design (link).

This story illustrates the possibility that a process of technology development may get locked into a particular approach that embodies substantial public risk, and it may be all but impossible to subsequently adopt a different approach. In another context Thomas Hughes refers to this as technological momentum, and it is clear that there are commercial, institutional, and regulatory reasons for this "stickiness" of a major technology once it is designed and adopted. In the case of nuclear power the inertia associated with light water reactors is particularly unfortunate, given that it blocked other solutions that were both safer and more economical.

(Here is a valuable review of safety issues in the nuclear power industry; link.)

Saturday, March 3, 2018

Consensus and mutual understanding

Groups make decisions through processes of discussion aimed at framing a given problem, outlining the group's objectives, and arriving at a plan for how to achieve the objectives in an intelligent way. This is true at multiple levels, from neighborhood block associations to corporate executive teams to the President's cabinet meetings. However, collective decision-making through extended discussion faces more challenges than is generally recognized. Processes of collective deliberation are often haphazard, incomplete, and indeterminate.

What is collective deliberation about? It is often the case that a collaborative group or team has a generally agreed-upon set of goals -- let's say reducing the high school dropout rate in a city or improving morale on the plant floor or deterring North Korean nuclear expansion. The group comes together to develop a strategy and a plan for achieving the goal. Comments are offered about how to think about the problem, what factors may be relevant to bringing the problem about, what interventions might have a positive effect on the problem. After a reasonable range of conversation the group arrives at a strategy for how to proceed.

An idealized version of group problem-solving makes this process both simple and logical. The group canvases the primary facts available about the problem and its causes. The group recognized that there may be multiple goods involved in the situation, so the primary objective needs to be considered in the context of the other valuable goods that are part of the same bundle of activity. The group canvases these various goods as well. The group then canvases the range of interventions that are feasible in the existing situation, along with the costs and benefits of each strategy. Finally, the group arrives at a consensus about which strategy is best, given everything we know about the dynamics of the situation.

But anyone who has been part of a strategy-oriented discussion asking diverse parties to think carefully about a problem that all participants care about will realize that the process is rarely so amenable to simple logical development. Instead, almost every statement offered in the discussion is both ambiguous to some extent and factually contestable. Outcomes are sensitive to differences in the levels of assertiveness of various participants. Opinions are advanced as facts, and there is insufficient effort expended to validate the assumptions that are being made. Outcomes are also sensitive to the order and structure of the agenda for discussion. And finally, discussions need to be summarized; but there are always interpretive choices that need to be made in summarizing a complex discussion. Points need to be assigned priority and cogency; and different scribes will have different judgments about these matters.

Here is a problem of group decision-making that is rarely recognized but seems pervasive in the real world. This is the problem of recurring misunderstandings and ambiguities within the group of the various statements and observations that are made. The parties proceed on the basis of frameworks of assumptions that differ substantially from one person to the next but are never fully exposed. One person asserts that the school day should be lengthened, imagining a Japanese model of high school. Another thinks back to her own high school experience and agrees, thinking that five hours of instruction may well be more effective for learning than four hours. They agree about the statement but they are thinking of very different changes.

The bandwidth of a collective conversation about a complicated problem is simply too narrow to permit ambiguities and factually errors to be tracked down and sorted out. The conversation is invariably incomplete, and often takes shape because of entirely irrelevant factors like who speaks first or most forcefully. It is as if the space of the discussion is in two dimensions, whereas the complexity of the problem under review is in three dimensions.

The problem is exacerbated by the fact that participants sometimes have their own agendas and hobby horses that they continually re-inject into the discussion under varying pretexts. As the group fumbles towards possible consensus these fixed points coming from a few participants either need to be ruled out or incorporated -- and neither is a fully satisfactory result. If the point is ruled out some participants will believe their inputs are not respected, but if it is incorporated then the consensus has been deformed from a more balanced view of the issue.

A common solution to the problems of group deliberation mentioned here is to assign an expert facilitator or "muse" for the group who is tasked to build up a synthesis of the discussion as it proceeds. But it is evident that the synthesis is underdetermined by the discussion. Some points will be given emphasis over others, and a very different story line could have been reached that leads to different outcomes. This is the Rashomon effect applied to group discussions.

A different solution is to think of group discussion as simply an aid to a single decision maker -- a chief executive who listens to the various points of view and then arrives at her own formulation of the problem and a solution strategy. But of course this approach abandons the idea of reaching a group consensus in favor of the simpler problem of an individual reaching his or her own interpretation of the problem and possible solutions based on input from others.

This is a problem for organizations, both formal and informal, because every organization attempts to decide what to do through some kind of exploratory discussion. It is also a problem for the theory of deliberative democracy (link, link).

This suggests that there is an important problem of collective rationality that has not been addressed either by philosophy or management studies: the problem of aggregating beliefs, perceptions, and values held by diverse members of a group onto a coherent statement of the problem, causes, and solutions for the issue under deliberation. We would like to be able to establish processes that lead to rational and effective solutions to problems that incorporate available facts and judgments. Further we would like the outcomes to be non-arbitrary -- that is, given an antecedent set of factual and normative beliefs by the participants, we would like to imagine that there is a relatively narrow band of policy solutions that will emerge as the consensus or decision. We have theories of social choice -- aggregation of fixed preferences. And we have theories of rational decision-making and planning. But a deliberative group discussion of an important problem is substantially more complex. We need a philosophy of the meeting!